Surrounded by supporters, opposition presidential candidate Henrique Capriles, center, gestures during a march before registering his candidacy for the presidency in Caracas, Venezuela, Sunday, June 10, 2012. (AP Photo/Fernando Llano)— AP

Opposition presidential candidate Henrique Capriles waves during a ceremony to register his candidacy for the presidency in Caracas, Venezuela, Sunday, June 10, 2012. Capriles will face Venezuela's President Hugo Chavez in the presidential elections scheduled for Oct. 7. (AP Photo/Ariana Cubillos)
/ AP

Supporters of opposition presidential candidate Henrique Capriles participate in a rally in front of the headquarters of the National Elections Council in Caracas, Venezuela, Sunday, June 10, 2012. Capriles registered his candidacy for the presidency and will face Venezuela's President Hugo Chavez in the presidential elections scheduled for Oct. 7. (AP Photo/Fernando Llano)— AP

Supporters of opposition presidential candidate Henrique Capriles participate in a rally in front of the headquarters of the National Elections Council in Caracas, Venezuela, Sunday, June 10, 2012. Capriles registered his candidacy for the presidency and will face Venezuela's President Hugo Chavez in the presidential elections scheduled for Oct. 7. (AP Photo/Fernando Llano)
/ AP

Opposition presidential candidate Henrique Capriles, left, receives a registration certificate at the headquarters of the National Elections Council in Caracas, Venezuela, Sunday, June 10, 2012. Capriles registered his candidacy for the presidency and will face Venezuela's President Hugo Chavez in the presidential elections scheduled for Oct. 7. (AP Photo/Ariana Cubillos)— AP

Opposition presidential candidate Henrique Capriles, left, receives a registration certificate at the headquarters of the National Elections Council in Caracas, Venezuela, Sunday, June 10, 2012. Capriles registered his candidacy for the presidency and will face Venezuela's President Hugo Chavez in the presidential elections scheduled for Oct. 7. (AP Photo/Ariana Cubillos)
/ AP

CARACAS, Venezuela 
Opposition leader Henrique Capriles marched through Venezuela's capital Sunday accompanied by hundreds of thousands of supporters as he formally launched his candidacy to run against President Hugo Chavez.

Surrounded by supporters waving red, yellow and blue Venezuelans flags, Capriles marched and jogged from a park in eastern Caracas toward the headquarters of the National Elections Council, 6 miles (10 kilometers) away, where he formally registered.

"I want to be everybody's president, not the president of a single group," Capriles told the crowd, repeating his theme that his campaign is trying to bridge the country's deep political divisions, in contrast to Chavez's often-inflammatory attacks on rivals.

Capriles has vowed to create jobs, fight crime and root out corruption, though most polls say he is trailing Chavez ahead of the Oct. 7 election.

"We have our hopes pinned on Capriles and we're sure he can lead us toward progress," said Sergio Mijares, a 58-year-old shopkeeper who opposes Chavez's plans to transform Venezuela into a socialist state. "I'm optimistic he can defeat Chavez."

Chavez, a former paratroop commander who is seeking a new six-year term in office, has sought to dismiss his rival by accusing him of representing the interests of the wealthy.

Capriles, meanwhile, has said his political approach is similar to that of former Brazilian President Luiz Inacio Lula da Silva, a leftist labor leader who promoted pro-business policies while financing expansive social programs as president that made him popular among the poor.

Capriles stepped down as governor of Miranda state this past week to focus on the campaign.

Chavez is scheduled to formally register his candidacy Monday, and the election campaign is heating up amid uncertainty regarding his health.

Chavez, 57, told journalists gathered at the presidential palace Saturday that he had undergone tests following his cancer treatment and everything came out well. The exams included imaging tests, which are used to check for the reappearance of tumors, he said.

The socialist leader returned home from Cuba on May 11 after what he said was a difficult round of radiation therapy. Over the past year, Chavez has undergone two surgeries that removed tumors from his pelvic region. Chavez has not disclosed details about his illness, including the type of cancer or the precise location of the tumors.

The president's medical treatment has forced him to limit his public appearances. Chavez says he has not yet begun campaigning. His challenger, meanwhile, has been traveling across the country to drum up support for his candidacy.

Andrea Reyes, a 48-year-old housewife, said she would vote for Capriles because of his reputation as an efficient administrator and out of fear that Chavez will ruin the economy and drive millions of Venezuelans to emigrate if he is re-elected.

"If Chavez emerges as the winner in October, he's going to destroy this country," she said.